This is quite a novel idea. Dark_Alex has been following Sony every step of the way, releasing a new version of his Open Edition firmware almost immediately after Sony releases their official update. Now, homebrew users have a pretty ingenious way of finding out if there's a new version of Dark_Alex's homebrew-enabled firmware: use Network Update! Long considered vile by homebrew users, Xandu and Team 280 have created a plugin that allows you to use PSP's firmware checker to download Dark_Alex's latest. Ironic, no?
Check out installation details at DCEmu. Of course, be warned: tampering with the BIOS of your system can lead to a brick. Also, the general success rate of this app hasn't been too high: only about 2/3 of users seem to be able to successfully connect to the Updater.